r286925 - [analyzer] Minor optimization: avoid setting state if unchanged

[Dominic Chen via cfe-commits]

Author: ddcc
Date: Mon Nov 14 19:40:58 2016
New Revision: 286925

URL: http://llvm.org/viewvc/llvm-project?rev=286925&view=rev
Log:
[analyzer] Minor optimization: avoid setting state if unchanged

Summary: Split out optimization from D26061

Reviewers: zaks.anna, dcoughlin

Subscribers: cfe-commits

Differential Revision: https://reviews.llvm.org/D26642

Modified:
    cfe/trunk/lib/StaticAnalyzer/Core/RangeConstraintManager.cpp

Modified: cfe/trunk/lib/StaticAnalyzer/Core/RangeConstraintManager.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/StaticAnalyzer/Core/RangeConstraintManager.cpp?rev=286925&r1=286924&r2=286925&view=diff
==============================================================================
--- cfe/trunk/lib/StaticAnalyzer/Core/RangeConstraintManager.cpp (original)
+++ cfe/trunk/lib/StaticAnalyzer/Core/RangeConstraintManager.cpp Mon Nov 14 19:40:58 2016
@@ -398,17 +398,19 @@ ConditionTruthVal RangeConstraintManager
 ProgramStateRef
 RangeConstraintManager::removeDeadBindings(ProgramStateRef state,
                                            SymbolReaper& SymReaper) {
-
+  bool Changed = false;
   ConstraintRangeTy CR = state->get<ConstraintRange>();
-  ConstraintRangeTy::Factory& CRFactory = state->get_context<ConstraintRange>();
+  ConstraintRangeTy::Factory &CRFactory = state->get_context<ConstraintRange>();
 
   for (ConstraintRangeTy::iterator I = CR.begin(), E = CR.end(); I != E; ++I) {
     SymbolRef sym = I.getKey();
-    if (SymReaper.maybeDead(sym))
+    if (SymReaper.maybeDead(sym)) {
+      Changed = true;
       CR = CRFactory.remove(CR, sym);
+    }
   }
 
-  return state->set<ConstraintRange>(CR);
+  return Changed ? state->set<ConstraintRange>(CR) : state;
 }
 
 RangeSet